The present invention relates generally to numerical control systems, and more particularly to a numerical control system for machine tools or robots, in which an object-oriented programming takes place, in that object classes are provided, from which in each case a number of objects can be formed, and a message mechanism existing for communication with other objects.
Such control systems are disclosed in VDI journal 133, no. 12, December 1991, Jurgen Schmidt et al. "Objektorientierte Projektierung von Steuerungssoftware" [Object-oriented user-configuration of control software], pages 60, 63-65.
The increasing diversity of applications for modern numerical control systems (NCSs) for machine tools or robots goes hand in hand with the necessity for the application-oriented configuration of NCS system behavior. Man-machine communication and the associated information handling are particularly subject to these growing requirements for flexibility.
Control systems which allow user-specific configuration and in this sense are referred to as "user-configurable" have defined degrees of freedom which allow purposeful configuration interventions in the application environment. Adapting the system behavior to the actual final application generally takes place in coordinated configuration phases by different target groups, i.e. in the specific case of NCS control technology starting with the groups, i.e. in the specific case of NCS control technology starting with the control system manufacturer, through to the machine manufacturer and ending up with the final machine user.
From a technical viewpoint there is consequently the requirement to provide control systems which operate in a new way, which initially have a universal form and subsequently are tailored globally and later locally to the actual final task.
To be able to perform the configuration procedure effectively, the overall requirements with the corresponding means of realizing them must be divided among the target groups involved in a way appropriate to their needs. Appropriate to their needs essentially means that the extent of the necessary instrumentation, the powerfulness of the integrated configuration tools and the granularity of the possibilities for intervention must in each case be brought into accord with the needs of the target group in question.
Existing approaches to the configuration of user-configurable NCS control systems usually concentrate on indirectly influencing the system behavior. For instance, the control system manufacturer defines in the development phase system interfaces which can be addressed by means of integrated or external configuration tools. In the simplest case, the means made available allow the mapping of application-specific parameters (for example machine parameters) onto internal system parameters, subsequently the storing of encoded description data (for example screen layout, operating sequences etc.) or else language-oriented command sequences (for example operating cycles) which are interpreted during the system run time. The powerfulness of the configuration tools used ranges from simple table editors to compiler structures which also allow the inclusion of application-specific algorithms. A target-group oriented graduation of the possibilities for intervention in the application environment is achieved-partly implicitly by locating the necessary configuration means system-externally or else system-internally by hierarchical access mechanisms.
Characteristic of existing solutions is the fact that the actual system behavior cannot be modified directly, because the fundamental hardware, data and program structures under the configuration interfaces are inflexibly predetermined by the usual approaches to implementation.
Furthermore, it should be noted that conventional configuration interfaces generally have an inadequate degree of system abstraction to allow them, for example, to be described for OEM applications (Original Equipment Manufacturing) and, in the final analysis, also do not offer any possibility of mapping technological application specifics which cannot be formulated algorithmically (for example technological empirical values).
Furthermore, reference is also made to EP-A-0 289 391, which shows as background for the prior art a modularly constructed numerical control system, which however does not allow simple alteration of the configuration. Furthermore, EP-A-0 304 071 discloses a data processing system which in very general terms is independent of an actual application and is in an object-oriented system environment, but this document does not provide a person skilled in the art with any suggestion of using such a system for a numerical control system, in particular a machine tool or robot control system. This document addresses a person skilled in data processing systems, for example in word processing or data base applications, because its intention is to facilitate the desired exchange of data within various data processing programs.
The present invention is directed to the problem of developing a numerical control system for machine tools or robots of which the initially universal form in the area of man-machine communication can be tailored in the simplest possible way to any applications, the associated information handling providing control data which can be processed in a universal manner by an integrated numerical control kernel and thus ensuring control of the machine or robot drives, including peripherals.